Cordeau and method of manufacturing same



Filed Oct. 4, 1935 "Patented June 8, 1937 CORDEAU AND METHOD OF ING SAME Walter Snelling, Allentown, Pa., assignur to Troian Powder Company, a corporation of New York Application October 4, 1935, Serial No. 43,590

6 Claims.

eter is thus elongated by pulling out to provide a long tube having thin walls, the explosive charge being similarly extended and drawn out. Cordeau is marketed generally on spools of five hundred foot lengths and it is, of course. highly 15 desirable that a continuous length of cordeau should be free of imperfections.

Under present methods of manufacture it has been found that as the lead tube is lengthened small holes or cracks develop, the average being one or two such imperfections to every thousand feet of cordeau. This is believed to be due to the formation of small spots of oxide or' the existence of impurities in the lead of the original tube, which impurities'or imperfections are 25 normally too small to be detected in any way now known to the art. However, under the present methods of rolling out or drawing out the lead tube these smallimperfections become greatly magnified with respect to the thickness of the 30 finished tube wall, and their presence causes a rupture in the wall which is, of course, detrimental to the use of the product and renders the same unsatisfactory and unfit for service. While this invention is particularly applicable 5 to the manufacture of cordeau as above described,

it is also applicable to the manufacture of any metallic sheathing or tubing irrespective of whether or not the sheathing or tubing is subsequently filled in the manufacture of 'a-finished 40 product. It is to be understood, therefore, that the details of the present disclosure are for purposes of illustration of a concrete embodiment of the principles of my invention and thatthe details disclosed may be varied as desired, and in 45 any respect not inconsistent with the scope of the invention as claimed. e

An object of this invention is the provision of anovel method of manufacturing malleable metal sheathing'or tubing of hollow form.

50 Another object is the provision of a novel method of manufacturing hollow lead tubing for rolling, swaglng er -drawing, in a manner to eliminate the possibility of ruptures due to the presence of impurities or imperfections in the I 65 body of the metal.

Another object is the provision of a method of manufacturing cordeau having superimposed concentric sheathing or tubing surrounding a detonatable core, the sheathing or tubing being separately formed and applied to produce the 5 finished product. V

A still further object of the invention is the provision of a novel construction of cordeau.

Other objects will be, apparent to those skilled in the art.

In the drawing:---

Figure 1 is a vertical sectional illustration of a simpleform of apparatus for carrying out certain steps in the manufacturing methods of this invention.

Figure 2 is a top plan view of the apparatus.

Figure 3 is a fragmentary perspective view of a section of cordeau as produced by the method of this invention.

The apparatus as shown in Figures 1 and 2 constitutes an illustrated embodiment of the means by-which the method may be practiced. In the form of apparatus as shown, there is provided a lead extrusion press having a body 4 arranged with a circular port in one side wall thereof and through which extends a concentric mandrel 5, the mandrel cooperating with the port to form a tube or sheath of lead 6 thereon as the lead is extruded through the port over the mandrel under the action of a piston 1 operating in the press 4 through the agency of any suitable means. Closely associated with the press '4 is a second press 8 having also a piston 9 working therein. This second press 8 is provided with transversely aligned ports through its opposite 3 sidewalls and the mandrel 5 extends axially through these ports and entirely through the press 8, the wall port on the side adjacent the press 4 being of a diameter equal to the diameter of the extrusion port in the wall of the press 4 40 while the port in the opposite wall of the press 8 is of a greater diameter. The press .8 contains also a charge of lead l0 which'is extruded through its discharge port in concentric superimposed relation with respect to the previously formed tube' or sheathing 6 that is forced over and along the mandrel 5 and through the 'press '8 under the action of the piston in the initial press 4.

In the practice of this invention the two associated presses 4 and 8, which may if desired be embodied in a unitary structure, are filled with a charge of lead and--- the press 4 isoperated in the usual manner to extrude a tube or sheath 6 of lead through its outlet ports along the mandrel 5 whence it travels along the mandrel intoand through the body of the press 8 and over the mandrel where it projects from the the opposite side of the press 8. While the initially formed sheath or tube 6 is traveling through the press 8 this second press is operated to cause the extrusion of a superimposed outer sheath or tube ll] of the lead directly upon the initially formed sheath or tube 6, the combined superimposed concentric layers traveling outwardly along the mandrel 5 to their point of take-off.

The entire structural assembly of the associated presses may be disposed out of contact with the air either in an evacuated space or in the presence of an atmosphere of a neutral gas so that there will be no possibility of any oxidizing coating forming on the initially formed sheath or tube prior to the application thereover of the second sheath or tube. This elimination of oxidization insures a complete bond between the concentric lead surfaces so that the two surfaces may be united by fusing or any desired subsequent operation in order to effect a direct bond.

Figure 3 illustrates a section of cordeau manufactured in accordance with this process and v tions is greatly reduced. By providing a tubing or sheathing as constructed in this manner of concentrically arranged superimposed sections, it will be apparent that any impurity or defect existing in one or the other of the sections will be out of registry with any possible defect or impurity existing in the other of the sections so that in the finished'product there will be no rupture of the tube or sheath. By this means it is immaterial whether or not any imperfections or impurities exist in either of the two sections so long as they do not register in the finished product. By the separate formation and superimposition of the outer and inner sheath the possibtility of a registry is infinitely small, the

chances under the present average occurrence of imperfection being, in fact, about one in one million.

As previously stated, after the double walled tube or sheath has been formed in the extruding operation, the two walls' are united by suitable fusing or welding and the tube is filled with the explosive core, being then drawn out and elongated by the usual means known to the art for the manufacture of cordeau.

Where desired, after the extrusion step, the

double walled tube may be filled with the explosive core and the composite filled tube drawn. rolled or swaged whereby simultaneously to unite the walls while very greatly increasing the length and reducing the diameter of the composite tube.

It will be understood that the invention is not restricted to the manufacture of double walled sheathing. or tubing of lead, it being equally applicable to the manufacture of sheathing or tubing of double walled construction formed of any malleable metal or of any metal capable of working in a manner to produce superimposed concentric sheaths or tubes.

I claim: I

1. The method of manufacturing cordeau which consists in forming a lead tube, superimposing directly thereupon in concentric relation a second lead tube, filling the inner tube with a core of detonating material, and drawing out the filled tube to provide the completed product.

2. The method of forming a malleable metal cordeau tube which consists in providing an inner tube of malleable metal, superimposing directly thereon in concentric relation an outer tube of the same malleable metal, and uniting the inner and outer tubes into a finished sheath.

3. A cordeau comprising a detonatable core, a malleable metal sheath surrounding said core, and a second malleable sheath of the same metal surrounding said first sheath in superimposed concentric relation and autogenously united with said first sheath after being superimposed thereon.

4. The method of manufacturing detonating fuse which consists in forming a tube of a malleable metal, superimposing thereupon in concentric relationship a second tube of the same malleable metal, filling the inner tube with acore of detonatable material, and drawing out the filled tube to provide the completed product.

5. The method of manufacturing cordeau which comprises covering a lead tube with a tightly fitting concentric lead tube, filling the inner tube with a core of detonatable material, and drawing out the composite filled tube to bond same and increase very greatly its length while reducing very greatly its diameter.

6. The method of manufacturing cordeau which comprises covering a-lead tube with a tight- 1y fitting concentric lead tube in a non-oxidizing atmosphere, filling the inner tube with a core of detonatable material, and drawing out the composite filled tube to unite the same while very greatly increasing its length and reducing its diameter.

WALTER O. SNELLING. 

